package com.demo.spark.rdddemo

/**
  * @program: hadoop
  * @description: ${description}
  * @author: Qiang.Ye
  * @date: 2019-06-27 07:23
  **/
object RddHigh {

  /**
    * （1）RDD的缓存机制
    *   >默认缓存在内存中，提高性能
    *   >可以缓存的位置是很多的：StorageLevel(默认使用persist cache)
    * val NONE : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val DISK_ONLY : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val DISK_ONLY_2 : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val MEMORY_ONLY : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val MEMORY_ONLY_2 : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val MEMORY_ONLY_SER : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val MEMORY_ONLY_SER_2 : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val MEMORY_AND_DISK : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val MEMORY_AND_DISK_2 : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val MEMORY_AND_DISK_SER : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val MEMORY_AND_DISK_SER_2 : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    * val OFF_HEAP : org.apache.spark.storage.StorageLevel = { /* compiled code */ }
    *
    *
    * （2）RDD的容错机制
    *   *>RDD的检查的是一种容错机制
    *   *>宽依赖，窄依赖
    *
    *
    *
    *
    */


}
